Radiographic Measurement Manual

Transcription

1 Spinal Deformity Study Group Radiographic Measurement Manual Editors in Chief Michael F. O Brien, MD Timothy R. Kuklo, MD Kathy M. Blanke, RN Lawrence G. Lenke, MD B T2 T5 T5 T12 +X T2 T12 +X -X CSVL T12 C7PL L2 A S Medtronic Sofamor Danek USA, Inc. 0 +

2

3 Radiographic Measurement Manual Editors in Chief Michael F. O Brien, MD Timothy R. Kuklo, MD Kathy M. Blanke, RN Lawrence G. Lenke, MD Section Editors Keith H. Bridwell, MD Kathy M. Blanke, RN Christopher L. Hamill, MD William C. Horton, MD Timothy R. Kuklo, MD Hubert B. Labelle, MD Lawrence G. Lenke, MD Michael F. O Brien, MD David W. Polly Jr, MD B. Stephens Richards III, MD Pierre Roussouly, MD James O. Sanders, MD 2008 Medtronic Sofamor Danek USA, Inc.

4 Acknowledgements Radiographic Measurement Manual The radiographic measurement manual has been developed to present standardized techniques for radiographic measurement. In addition, this manual will serve as a complimentary guide for the Spinal Deformity Study Group s radiographic measurement software. Special thanks to the following members of the Spinal Deformity Study Group in the development of this manual. Sigurd Berven, MD Hubert B. Labelle, MD Randal Betz, MD Lawrence G. Lenke, MD Fabien D. Bitan, MD Thomas G. Lowe, MD John T. Braun, MD John P. Lubicky, MD Keith H. Bridwell, MD Steven M. Mardjetko, MD Courtney W. Brown, MD Richard E. McCarthy, MD Daniel H. Chopin, MD Andrew A. Merola, MD Edgar G. Dawson, MD Michael Neuwirth, MD Christopher DeWald, MD Peter O. Newton, MD Mohammad Diab, MD Michael F. O Brien, MD John Dimar, MD James Ogilvie, MD John P. Dormans, MD Stephen Ondra, MD Denis Drummond, MD George Picetti, MD Jean Dubousset, MD David W. Polly, MD John B. Emans, MD Rolando Puno, MD Jean-Pierre Farcy, MD B. Stephens Richards, MD Steven D. Glassman, MD Pierre Roussouly, MD Christopher L. Hamill, MD David P. Roye, MD Darrell S. Hanson, MD James O. Sanders, MD William C. Horton, MD John Sarwark, MD M. Timothy Hresko, MD Frank J. Schwab, MD Serena Shaw Hu, MD Paul D. Sponseller, MD Kamal N. Ibrahim, MD Daniel J. Sucato, MD, MS Charles E. Johnston, MD Se-il Suk, MD Noriaki Kawakami, MD Jeffrey D. Thomson, MD Andrew G. King, MD Ensor Transfeldt, MD Timothy R. Kuklo, MD, JD Mark Weidenbaum, MD John Kostuik, MD Stuart Weinstein, MD Additional contributors: Kathy Blanke, RN Eric Berthonnaud, PhD Oscar Carbonell, RT Jim Clayton (Illustrator) Joannes Dimnet, PhD JoAnn Jones, BS Shari L. Mitchell, MA Raymarla Pinteric, MT Teresa Schroeder, MBA Shea Snow (Designer) Doug Trotter, MS/MA

5 Keith H. Bridwell, MD Preface Over the last several decades, the Cobb measurement performed on radiographs has been the most universally used method to characterize a spinal deformity. However, the Cobb measurement does not describe all of the important characteristics of a spinal deformity. The Radiographic Measurement Manual (RMM) describes many of the intricacies of spinal deformity, such as vertebral numbering, segmental sagittal alignment, lumbosacral transitional vertebra, the correct standing posture for long cassette coronal and sagittal radiographs, the tidemark for an acceptable versus unacceptable long cassette radiograph, parameters for assessment of spinal flexibility in the coronal and sagittal planes, how to obtain useful clinical photographs, and a classification strategy for adolescent idiopathic scoliosis (AIS). In addition, it details measurement techniques for coronal and sagittal balance, apical deviation, vertebral rotation, and how to define the end, neutral, and stable vertebrae, which are critical in the assessment of spinal deformities. In spite of this detail we must acknowledge that certain regions of the spine remain difficult to reproducibly assess, especially in the sagittal plane. This is particularly true of the proximal thoracic spine where it is overlapped by the shoulder girdle from T1 to T8. This region remains challenging to radiographically visualize and assess, even in thin patients. Also included in this manual are measurement parameters that are specific for adult deformity. In particular, rotatory subluxations are quite difficult to measure in a reproducible fashion. The Spinal Deformity Study Group has spent many hours and numerous conferences reaching a consensus on how to measure these deformities. Achieving one hundred percent agreement on these parameters has not been possible, but consensus has been achieved and I personally feel that this manual addresses how to measure adult rotatory olisthesis far better than any current textbook. The parameters of spondylolisthesis are comprehensively depicted. Meyerding s classification is most commonly used to describe spondylolisthesis. However, we know that two individuals with a grade 4 spondylolisthesis may look and clinically behave quite differently because of differences in the slip angle, pelvic tilt, sacral slope, and the pelvic incidence. All of these alternative techniques to describe spondylolisthesis are clearly depicted in the spondylolisthesis section. The benefits of a standardized measurement manual are countless. This manual provides clear text and outstanding radiographic and illustrative detail to define the important parameters that describe spinal deformity. As you will see, the quality of the illustrations and radiographs are unsurpassed by any textbook or peer-review journal. It is common even in peer-review journals to see long cassette radiographs published that are so shrunken in size that important radiographic details and spinal balance cannot be appreciated by the reader. I can only hope that major publishers will look at this manual and adopt these standards for clarity and size of reproduction for long cassette films. This Radiographic Measurement Manual will finally provide researchers and clinicians a common language to discuss spinal deformity. All physician members of the Spinal Deformity Study Group are members of the Scoliosis Research Society (SRS). I would encourage all members of the SRS to adopt this manual as a reference. It is a tremendous resource, not only for clinical research, but also for day-to-day practice. I am hopeful that when medical students and orthopaedic and neurosurgery residents see this manual that they will be inspired to devote their careers to the study of spinal deformity and related clinical research. I would be remiss if I did not mention the names of several mentors who have inspired all of us. These spinal surgeons have been responsible for the rapid growth and advancement of spinal deformity research and treatment over the last 40 years. Notable in this group are Marc Asher, MD; David Bradford, MD; Yves Cotrel, MD; Ronald DeWald, MD; Jean Dubousset, MD; Jürgen Harms, MD; Kenton Leatherman, MD; Dean MacEwen, MD; John Moe, MD; Thomas Whitesides Jr, MD; and Robert Winter, MD. I am saddened that Edgar Dawson, MD, who was very active in the Spinal Deformity Study Group, could not see this final product. He would have been proud. I wish to recognize and thank David Poley and Michael Ferguson at Medtronic for their continuous support of the Spinal Deformity Study Group and for making this landmark project possible. Also, Randal Betz, MD, Co-Chairman of the study group, deserves special recognition for the instrumental role he has played in the group s foundation and in its tremendous accomplishments. In conclusion, my hat goes off to the chief editors, Michael O Brien, MD; Timothy Kuklo, MD; Lawrence Lenke, MD; and Kathy Blanke, RN, who have spent endless hours working on precise definitions and illustrations to achieve consensus on these measurements. Significant time and effort has been put forth over three years to finalize this manual. Recognition is also given to the section editors and members of the Spinal Deformity Study Group who have participated in this project. And finally special thanks and appreciation must be given to JoAnn Jones with Medtronic for her tireless support and assistance in bringing this book to publication. Congratulations! Keith H. Bridwell, MD St. Louis, Missouri USA

6 Harry Shufflebarger, MD Preface (continued) The collection and production of this standardized set of radiographs, illustrations, and photographs represent an enormous effort. The result is an excellent and highly user-friendly textbook. The written explanations accompanying the figures throughout the text are clear and concise. The section on clinical photography provides a standardized methodology to produce clinical photographs of patients acceptable for any need. The same may be said for the instructions on obtaining and capturing radiographic images. The section on adolescent idiopathic scoliosis provides one-stop shopping for all clinically relevant measurements. This in itself is an excellent contribution to the spinal community. The adult deformity section repeats many of the measurements described in the adolescent chapter, with additional measurements specific for adult onset degenerative scoliosis. The spondylolisthesis section will familiarize the reader with all measurements pertinent to this condition, and to accurately utilize them clinically. Drs. O Brien, Kuklo, Lenke, and Kathy Blanke, RN, are to be congratulated on producing such a simple but immensely useful reference textbook. There should be little question in the future as to how a particular measurement is correctly made. Harry Shufflebarger, MD Miami, Florida USA From the Editors In Chief: We wish to extend special acknowledgment to JoAnn Jones for her patience, drive, and dedication to the development of the Radiographic Measurement Manual. Her unyielding and cheerful support through many changes is greatly appreciated. Her superb assistance has made the entire process easier. Thanks JoAnn, we couldn t have done it without you! Mike, Tim, Kathy, and Larry

7 Table of Contents Radiographic Measurement Manual Chapter 1: Spinal Anatomy and Alignment... 1 Chapter 2: Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity...11 Chapter 3: The Lenke Classification: Technique for Analysis and Classification of Operative AIS...31 Chapter 4: Adolescent Idiopathic Scoliosis...47 Chapter 5: Adult Deformity...71 Chapter 6: Spondylolisthesis...95 Glossary of Terms and Guidelines for Measuring

8

9 Chapter 1 Spinal Anatomy and Alignment C2 C7 T1 T12 L1 L5 (ICL) Section Editors: Michael F. O Brien, MD Lawrence G. Lenke, MD Timothy R. Kuklo, MD Kathy M. Blanke, RN 1

10 Chapter 1 Spinal Anatomy and Alignment Introduction Understanding normal spinal anatomy is a prerequisite to identifying, describing, and treating spinal deformity. Without a clear understanding of normal anatomy, one cannot understand the importance or implications of the sometimes subtle anatomic variations identified in spinal deformity. Only with a clear understanding of both normal and altered anatomy will the surgeon be able to effectively interpret the radiographic images and formulate a plan to correct spinal deformities. In addition to visualizing and understanding the anatomic variations present in spinal deformity, it is essential that the deformity can be reliably described in a quantitative fashion. Quantifying the deformity facilitates developing a clear understanding of the important structural features of the altered spinal anatomy necessary to develop an effective treatment plan. Equally important, it facilitates accurate communication between healthcare providers regarding the important features of the deformity so that comparative analysis of alternative treatment regimens can be undertaken for similar deformities. Although a detailed description of spinal anatomy is beyond the scope of this current work, it is germane to briefly touch on normal spinal anatomy. There are four distinct regions of the spine: cervical, thoracic, lumbar, and sacropelvic. Each region is separated by transition zones: craniocervical, cervicothoracic, thoracolumbar, and lumbosacropelvic. These transition zones represent areas of anatomic metamorphoses between spinal regions. It is important to understand the unique anatomy, biomechanics, and alignment of each of these regions of the normal spine. Only then can an appreciation be developed for the consequences of spinal deformity so that an effective surgical plan can be created. Abnormalities in embryologic, osseous, and neurologic development may precipitate the development of spinal deformities. Segmentation defects caused by abnormalities in embryologic development may result in osseous pathology, such as hemivertebra, block vertebra, and bars. Alterations in neurologic development may result in abnormalities of the central nervous system, including syringomyelia, Chiari malformations, split cords, and tethered cords. Other more subtle abnormalities, such as alteration in CNS pathways for balance and spinal reflexes, and disturbances in melatonin production, have been implicated in what has been described as idiopathic spinal deformity. It is, therefore, clear that a detailed understanding of normal spinal anatomy and the possible pathologic entities that can disturb it are important in developing an understanding of spinal deformity. Anatomy One of the simplest descriptors of spinal anatomy is often overlooked: vertebral numbering. Having a consistent method of vertebral labeling is important in developing a detailed description of both normal and altered spinal anatomy. In the normal spine the cervical region consists of the skull base (C0) and seven mobile segments: C1-C7. The thoracic spine has 12 mobile segments: T1-T12. Each thoracic segment has a pair of ribs that articulate with the named vertebral body. The ribs from T1-T10 are usually joined anteriorly at the costochondral junction or sternum. T11 and T12 usually have floating ribs, which are not connected anteriorly to the rib cage. The normal lumbar spine has five mobile segments: L1-L5. The sacropelvic unit consists of the sacrum/coccyx and the bilateral ilium. The sacrum is comprised of five fused segments that articulate with the ilium through the SI joints bilaterally (see Figures 1A and 1B). 2

11 Spinal Anatomy and Alignment Vertebral Numbering When the patient s spinal anatomy is normal, numbering the spinal segments is relatively easy. This may not be the case when evaluating a spine with atypical segments or when a spinal deformity is present. It is essential when describing a spinal deformity that a consistent method for vertebral numbering be employed. Failure in this regard will result in miscommunication about the deformity or worse, surgical interventions which are performed at the wrong levels due to mislabeling. The cervical vertebrae are seldom involved in spinal deformity. Therefore, numeric labeling of these segments is usually not an issue for the deformity surgeon. More importantly, there is seldom any variation in the number of cervical segments, remaining fairly consistent at seven. In congenital and Klippel-Feil abnormalities, the number of mobile segments may be fewer because of congenital fusions, but seven cervical segments can usually be identified. Numbering commences from the atlas (C1). T1 is defined as the first vertebra with a pair of associated ribs. All vertebrae distal to T1 with associated ribs are defined as thoracic. Usually there are 12 thoracic vertebrae. The most common variations are 11 or 13 thoracic segments (see Figures 2A and 2B, 3A and 3B). Identifying the terminal thoracic vertebra is not always a simple matter, since distinguishing between a very small rib or a thin elongated transverse process may be difficult. Occasionally this distinction can only be made intraoperatively by direct inspection and manual palpation of the transverse process/rib anatomy. The determination of the terminal thoracic vertebra should not affect surgical planning. It may, however, affect the final labeling of the spinal segments. L1 will always be the vertebra immediately below the last thoracic vertebra, that is the last vertebra with an associated pair of ribs. The lumbar spine typically has five vertebrae, but may occasionally have four or six segments. It is not mandatory that the overall number of spinal segments be conserved at 24 ( i.e., 7 cervical + 12 thoracic + 5 lumbar = 24). It is possible that a patient may have 13 thoracic vertebrae and six lumbar vertebrae. It is more common, however, that the number of spinal segments are conserved. For example, a patient with 11 thoracic vertebrae will usually have 6 lumbar vertebrae and a patient with 13 thoracic vertebrae will have 4 lumbar vertebrae. Another area where errors in vertebral labeling may occur is at the lumbosacral junction. The last lumbar vertebra may be partially or fully sacralized or the first sacral vertebra may be lumbarized. Castelvi et al. have nicely detailed the possible osseous variations at the lumbosacral junction (see Figure 4). These may involve unilateral or bilateral articulation of the transverse process of L5 with the ilium and/or the sacrum. This may create the appearance of a segmented S1 S2 or an asymmetric or abnormally formed sacral ala on one or both sides. As with variations at the thoracolumbar junction, vertebral labeling inconsistencies at the lumbosacral junction should not interfere with the development or implementation of an appropriate surgical plan. Failure to take these variations into account may result in wrong level surgery if a consistent labeling scheme is not agreed upon by all involved in the care of the patient. Accurate labeling of the vertebral segments is important in our ability to communicate a detailed description of the spinal anatomy, whether normal or pathologic. It is also important for clearly identifying vertebral levels intra-operatively. With the advent of CT scans and MRIs, a clear understanding of the anatomy can be achieved in most cases. Once the anatomy is clearly visualized, the pathology can be described and effective surgical plans can be formulated. Steps for labeling and measuring normal and atypical vertebrae: 1. Start at the first vertebra with ribs and call that T1. 2. Continue labeling vertebrae until the last one with ribs is identified (it could be T11, 12, or 13). 3. If there are 11 definite ribs with 6 vertebrae below and it is not clear if the 12th vertebra has a rib, call it T12 to maintain the 12 Thoracic and 5 Lumbar numbering. 4. In all other cases, the first vertebra below the last thoracic vertebra (last vertebra with ribs) is considered L1. 5. The L5 junction is reviewed for lumbarization or sacralization of the transitional vertebra. If L5 is sacralized it is still necessary to measure coronal and sagittal Cobbs to S1 (versus L5) and also measure the sagittal balance from C7 to S1 (versus L5). 3

12 Spinal Anatomy and Alignment Sagittal Alignment The spine has characteristic alignment in the coronal and sagittal planes. In the coronal (frontal) plane the spine is straight. In the sagittal (lateral) plane, the spine is lordotic in the cervical and lumbar regions and kyphotic in the thoracic region. There is a wide range of normal sagittal profiles for each region. Initially, these regional alignments were discussed in terms of fixed absolute values. However, with an improved understanding of the importance of the sacropelvic foundation, which is discussed and diagrammatically detailed in the spondylolisthesis section, a wide range of normals are now considered likely. It is possible that each individual has specific requirements for cervical/lumbar lordosis and thoracic kyphosis because of unique fixed pelvic relations. The lordotic and kyphotic segments of the spine must ultimately balance the occiput over the sacropelvic axis in an energy efficient position. The C7 plumbline (C7PL) should pass within a few millimeters of the posterior superior corner of S1. The thoracic spine should have approximately 10 to 40 of kyphosis and the lumbar spine should have approximately 40 to 60 of lordosis. The lumbar spine should arithmetically have 30 more lordosis than thoracic kyphosis (i.e., 60 of lumbar lordosis should be accompanied by 30 of thoracic kyphosis). It is clear from this brief discussion that understanding normal and abnormal spinal anatomy and our ability to clearly describe it is important. This knowledge is at the heart of our ability to develop and implement treatment options for spinal deformity. It is also necessary so that we can evaluate the effect of our interventions and compare alternative treatments for similar deformities. If there are an atypical number of vertebrae, the sagittal measures will be performed as shown in Table 1 below. The thoracolumbar region (T10-L2) will remain constant regardless of the number of vertebral bodies in that region. For example, it is possible to have one extra vertebra if there are thirteen thoracic segments or one less vertebra if there are eleven thoracic segments. 4 Table 1 Normal 12 Thoracic/5 Lumbar T5-T12 T10-L2 T12-S1 Atypical 11 Thoracic/6 Lumbar T5-"T12"* T10-L2 "T12"-S1* Suggested Reading 11 Thoracic/5 Lumbar T5-T11 T10-L2 T11-S1 11 Thoracic/4 Lumbar T5-T11 T10-L2 T11-S1 13 Thoracic/4 Lumbar T5-T12 T10-L2 T12-S1 13 thoracic/5 Lumbar T5-T12 T10-L2 T12-S1 * See step 3 of labeling and measuring under atypical vertebra and Figure 2a and 2b on page O Brien MF, Lenke LG, Mardjetko S, et al. Pedicle morphology in thoracic adolescent idiopathic scoliosis: Is pedicle fixation an anatomically viable technique? Spine. 2000;25: Zindrick M, Wiltse L, Doornik A: Analysis of the morphometric characteristics of the thoracic and lumbar pedicles. Spine. 1987;12: Bernhardt M, Bridwell KH. Segmental analysis of the sagittal plane alignment of the normal thoracic and lumbar spines and thoracolumbar junction. Spine. 1989;14: Arlet V. Surgical Anatomy of the Sacrum and Pelvis. In: Spinal Deformities: The Comprehensive Text, DeWald R, Ed. Thieme, NY, NY Arlet V. Surgical Anatomy of the Lumbar Spine. In: Spinal Deformities: The Comprehensive Text, DeWald R, Ed. Thieme, NY, NY OBrien M. Surgical Anatomy of the Thoracic Spine. In: Spinal Deformities: The Comprehensive Text, DeWald R, Ed. Thieme, NY, NY OBrien M. Surgical Anatomy of the Cervical Spine. In: Spinal Deformities: The Comprehensive Text, DeWald R, Ed. Thieme, NY, NY Netter FH, Colacino S. Atlas of Human Anatomy: Sections 1 and 2. Ciba-Geigy, Summit, NJ Castelvi AE, Goldstien LA, Chan DPK. Lumbosacral Transitional Vertebra and their relationship with lumbar extradural defects. Spine. 9: , Weinstien SL, ed. The Pediatric Spine, Principles and Practice. Lippincott Williams and Wilkins, 2001.

13 Spinal Anatomy and Alignment Suggested Reading 11. Legaye J, Duval-Beaupre G, Hecquet J, et al. Pelvic Incidence: A Fundamental Pelvic Parameter for Three Dimensional Regulation of Spinal Sagittal Curves. Eur Spine J. 1998;7: Jackson R, Kanemura T, Kawakami N, Hales C. Lumbopelvic Lordosis and Pelvic Balance on Repeated Standing Lateral Radiographs of Adult Volunteers and Untreated Patients with Constant Low Back Pain. Spine. 2000;25: Gelb D, Lenke L, Bridwell K, Blanke K, McEnery K. An analysis of sagittal spinal alignment in 100 asymptomatic middle and older aged volunteers. Spine. 1995;20: Jackson R, McManus A. Radiographic analysis of sagittal plane alignment and balance in standing volunteers and patients with low back pain matched for age, sex, and size: A prospective controlled clinical study. Spine. 1994;19: Jackson R, Peterson, McManus A, Hales C. Compensatory spinopelvic balance over the hip axis and better reliability in measuring lordosis to the pelvic radius on standing lateral radiographs of adult volunteers and patients. Spine. 1998;23: Vedantam R, Lenke L, Keeney J, Bridwell K. Comparison of standing sagittal spinal alignment in asymptomatic adolescents and adults. Spine. 1998;23:

14 Spinal Anatomy and Alignment Normal Anatomy 12 Thoracic and 5 Lumbar Vertebrae Figure 1a C2 Figure 1b C2 C7 T1 C7 T1 T12 L1 T12 L5 (ICL) L5 6 Note that the position of the intercrestal line (ICL) confirms the location of L5 on AP and lateral x-rays.

15 Spinal Anatomy and Alignment Atypical Anatomy 11 Thoracic and 6 Lumbar Vertebrae* Figure 2a C2 Figure 2b C2 C7 T1 C7 T1 T11 L1 (T12) T11 (T12) L1 L6 (L5) (ICL) (L5) L6 *If there are 11 definite ribs with 6 vertebrae below and it is not clear if the 12th vertebra has a rib, call it T12 to maintain the 12 Thoracic and 5 Lumbar numbering. Note that the position of the intercrestal line (ICL) confirms the location of L6 (L5) on AP and lateral x-rays. 7

16 Spinal Anatomy and Alignment Atypical Anatomy 13 Thoracic and 4 Lumbar Vertebrae Figure 3a C2 Figure 3b C2 C7 T1 C7 T1 T13 L1 T13 L1 L4 (ICL) L4 Note that the position of the intercrestal line (ICL) confirms the location of L4 on AP and lateral x-rays. 8

17 Spinal Anatomy and Alignment Lumbosacral Transitional Vertebrae Normal L5 S1 Castelvi IIA Figure 4a L5 S1 Castelvi IIIA Figure 4b L5 S1 Figure 4c Castelvi AE, Goldstien LA, Chan DPK. Lumbosacral Transitional Vertebra and their relationship with lumbar extradural defects. Spine. 1984;9:

18

19 Chapter 2 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Section Editors: Kathy M. Blanke, RN Timothy R. Kuklo, MD Michael F. O Brien, MD Lawrence G. Lenke, MD 11

20 Chapter 2 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Producing Radiographic Images In order to produce a high quality diagnostic film from the cervicothoracic junction to the pelvis for the purpose of evaluating spinal deformities, several factors must be taken into consideration. First, proper distance from the source to the image is important. A distance of 72" produces an acceptable amount of magnification and distortion and is therefore preferred. The use of a compensating filter between the patient and the x-ray beam assures that proper density is maintained between the easily penetrated thoracic cavity and the denser lumbosacral region. Proper placement of a gonad shield may be utilized to protect the patient but should not cover important osseous anatomy. Variations in grid ratios, film/screen combinations, x-ray machine generators, and patient size and shape make establishing exact recommendations for appropriate exposure of scoliosis films impossible. Since final exposures are dependent on many variables, radiographic quality may vary between institutions and from department to department. Therefore, for the spinal deformity surgeon, it is essential to identify radiology technicians that can reliably manipulate all the variables in order to produce consistent images that clearly delineate the osseous anatomy to be evaluated and measured. As a reminder, all radiographs, including those for spondylolisthesis, are taken in an upright position to show the true position of the spine. This excludes various flexibility films discussed later in this chapter. If the leg length discrepancy is > 2cm, the x-ray should be taken with a block to level the pelvis. 12

21 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Stance for Scoliosis X-rays Radiographic Methodology Patients should stand with their knees locked, the feet should be shoulder width apart, looking straight ahead with their elbows bent and knuckles in the supraclavicular fossa bilaterally. This will place the patient s arms at approximately a 45 angle to the vertical axis of the body (Figures 1 4). If there is greater than a 2 cm leg length discrepancy, the x-ray should be taken with a block to level the pelvis. NOTE: Remove rings, bracelets, earrings (all jewelry) before taking x-rays to avoid artifact. Figure 1 Figure 2 Figure 3 Figure 4 Types of X-rays Optimal Quality and Unacceptable Views 1) Mandatory Radiographs for Surgical Planning: a) Standing AP or PA (Figures 5 9 Acceptable/Figures Unacceptable) b) Supine sidebenders: either two long cassettes or three 14" x 17"s (one each for the proximal thoracic, main thoracic, thoracolumbar/lumbar). All 3 curves must be evaluated for flexibility. (Figures Acceptable/Figures Unacceptable) c) Standing lateral (Figure 20 Acceptable/Figures Unacceptable) 2) Optional Radiographs (Flexibility): a) Push-prone (Figures 24 29) b) Supine AP (Figures 30 31) c) Fulcrum bend (thoracic curve) (Figures 32 34) d) Traction AP (Figures 35 37) e) Supine hyperextension crosstable lateral (Figures 38 40) 13

22 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Mandatory Radiographs: 1a. Standing AP or PA Acceptable Images Good quality spinal radiographs will show C7 to the femoral heads and the entire rib cage from right to left. (Figures 5 and 6) Figure 5 Figure 6 If unable to assess the TRC (triradiate cartilage) on an otherwise acceptable standing AP/PA x-ray, it may be visible on one of the flexibility x-rays. 14 Figure 7 Figure 8 Supine

23 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Mandatory Radiographs: 1a. Standing AP or PA Acceptable Images It is not uncommon to have a good quality spinal radiograph showing C7 to the sacrum but not the ribcage or triradiate cartilage. All vertebrae must be visible for the radiograph to be deemed acceptable. Mandatory Radiographs: 1a. Standing AP or PA Unacceptable Images Figure 9 14" x 17" films without a clear and complete view of the pelvis (right and left iliac wings), C7, and S1. Figure 10 15

24 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Mandatory Radiographs: 1a. Standing AP or PA Unacceptable Images Image blurred Image too light or dark or both Can t see C7, T1 at the top Can t see anything at the bottom Figure 11 Figure 12 Can t see C7 or T1 Belt buckle, etc. covering critical landmarks Bad tape job. (upper part of film flipped and taped incorrectly) Image flipped Don t tape over spine Figure 13 Can t see S1 16 Figure 14

25 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Mandatory Radiographs: 1b. Supine Sidebenders Mandatory that all three curves are visualized Bending films of the proximal thoracic and lumbar curves are seen on the left sidebender for right thoracic curves. Need to see the entire spine. Main thoracic (typically right sidebender) Figure 15 Figure 16 Figure 17 Bending films of all three curves are necessary for accurate curve classification. If minor curves are small (< 25 ) on the upright image and the sagittal plane is within normal limits, one can assume that those curves are nonstructural. Conversely, if structural characteristics of a minor curve are suspected (the PT curve in this example) and the sagittal plane is normal, there is no way to determine if that curve is structural without a bending film. (If T2-T5 is 20 on the upright sagittal film, then the PT curve is structural regardless of the bending measurement.) It is good practice to have bending films of all three curves to assess flexibility. No proximal thoracic bender Figure 18 Figure 19 17

26 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Mandatory Radiographs: 1c. Standing Lateral Acceptable Image Radiograph should be obtained with patient s left side against the cassette (patient facing the observer s right). The radiograph should include C7 to S1. The ability to visualize C0 C1 and the hip joints is optimal. It is not uncommon to have a good quality radiograph where T2 is not clear but all other landmarks (C7, T5, T10, T12, L2, and the sacrum) are visible. The upper thoracic spine is the most difficult area to image. Figure 20 1c. Standing Lateral - Unacceptable Images Whited out at top Figure 22 14" x 17" lateral can t see C7, T2, or S1 Image blurred 18 Figure 21 Figure 23

27 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Optional Views: 2a. Push Prone Apply pressure to push on the structural curve(s) while stabilizing point(s) on the opposite side of the body. UPRIGHT PUSH PRONE Single curves: Push on the major curve and stabilize the opposite pelvis and axilla. Thoracic curves: Need to push lower than horizontal to the apex of the curve push on ribs that attach to the apex. Stabilize the opposite pelvis and axilla. Figure 24 Figure 25 UPRIGHT PUSH PRONE Thoracolumbar/Lumbar Curves: Need to push on the curve between the rib cage and iliac crest. Stabilize the opposite pelvis and axilla. Figure 26 Figure 27 19

28 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Optional Views: 2a. Push Prone Double Major Curves Push on both curves - stabilize the axilla opposite the MT curve and the pelvis opposite the thoracolumbar/ lumbar curve. UPRIGHT PUSH PRONE Figure 28 Figure 29 Optional Views: 2b. Supine AP UPRIGHT SUPINE 20 Figure 30 Figure 31

29 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Optional Views: 2c. Fulcrum Bend (Thoracic Curve) Patient side bending over a bolster positioned under the most prominent part of the ribcage (ribs that attach to apex of curve). The arms are positioned overhead and the body should be relaxed over the bolster, which is firm enough so that the shoulder and hip does not touch the x-ray table. Figure 32 UPRIGHT FULCRUM BEND X marks location of bolster Figure 33 Figure 34 21

30 Optional Views: 2d. Traction AP Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Figure 35 UPRIGHT TRACTION FILM Although bending films are the most common method to assess curve flexibility, traction films may also be useful. Use of a head halter, as shown above, or simply pulling from the axilla of both upper extremities is effective for creating the cephalad vector. The force applied should be firm but not painful. Figure 36 Figure 37 22

31 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Optional Views: 2e. Supine Hyperextension Crosstable Lateral (Bolster under Apex of Kyphosis) Figure 38 UPRIGHT HYPEREXTENSION LATERAL X marks location of bolster Figure 39 Figure 40 23

32 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Clinical Photographs: Defining a treatment plan for scoliosis is multifactorial. It involves a clinical and a radiographic evaluation and a detailed discussion with the patient and the family. In some cases the treatment option is clear. In other cases there are multiple treatment options with the final plan being determined by the nuances of the deformity and the goals of surgery. A critical component in the assessment of spinal deformity is the visual inspection of the spine: rib and/or flank prominences, shoulder level, coronal and sagittal balance, and overall balance and appearance. Appropriate clinical photography is the means to catalog this visual inspection. Photography has been used in the clinical setting for nearly 100 years. It is an important component in the routine diagnosis and treatment of patients with spinal deformity and is not primarily an investigational or research tool. Clinical photography parallels and augments the clinical examination. It allows documentation of subtle visual and structural components of the deformity. Clinical photography also allows multiple clinician input when direct examination of the patient is not possible. It also facilitates accurate serial comparisons over time and allows comparison of preoperative and postoperative spinal alignment. In addition, it provides a research tool that can be used to enhance current and future patient care. Because the clinical photos require a relative state of undress it is necessary to maintain the patient s privacy and dignity. For this reason, clinical photography should be performed in a respectful fashion and secured as part of the medical record. As part of the medical record, it must be accorded the same confidentiality as other sensitive medical information. The patient s facial appearance adds no value to the spinal deformity evaluation. Therefore, appropriate masking of the face can be performed to assure patient privacy. Patient and parent/guardian consent will be obtained if the patient is a minor. Ideal Clinical Photos: Clinical photos should be taken without any clothing on the trunk. Shorts or underwear should be below the waist to allow visualization of the LS junction and iliac crests. Long hair must be up off the shoulders. This allows full visualization/evaluation of all aspects of the deformity. Photos should be cropped to obscure the face to protect patient identity. Females should position their arms to cover their breasts. The best position of the arms for lateral clinical photos has not been documented. Options are arms at the side of the torso, crossed over the chest, or in front of the body at a angle. Photography Views - Optimal (Figures 41-54) and Suboptimal Examples (Figures 55-62) Upright posterior trunk hair off shoulders (mandatory) Close forward bend posterior (mandatory) Upright lateral both sides (optional) Close forward bend lateral to highlight prominence from both sides if applicable (optional) On the following pages are three representative cases with acceptable clinical photos. 24

33 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Optimal Clinical Photos: Case 1. Figure 41 Figure 42 Figure 43 Figure 44 25

34 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Optimal Clinical Photos: Case 2. Figure 45 Figure 46 Figure 47 Figure Figure 48 Figure 49

35 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Optimal Clinical Photos: Case 3. Figure 50 Figure 51 Figure 52 Figure 33 Figure 53 Figure 54 27

36 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Suboptimal Clinical Photos The bra obscures full appreciation of the thoracic prominence. Figure 55 Figure 56 A bra, a strap tied in the back, or long hair obscures full appreciation of the thoracic prominence on the forward-bending view. Figure 57 Figure 58 Figure 59 28

37 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Suboptimal Clinical Photos Long hair, hospital gowns, bulky halter tops, or shorts positioned above the hips will obscure full appreciation of all aspects of the deformity. Figure 61 Figure 60 Figure 62 If you are unable to take pictures of female patients without any clothing on the trunk, the following page has information for use of a halter top that does not obscure visualization of the deformity. 29

38 Halter Tops Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Straps Left 7 top and bottom, Right 18 top, 36 bottom Measurements (cut larger for seams) Top Width Bottom Width Vertical Length SM MED LG Stitched here so ties won t move. Straps are narrow bias tape or cording. Front views of halter: The short ties should be on the left side of the halter so when tied, bows are on the patient s left side (since lateral photos are usually taken with the patient facing right). You can untie the waist strap for pictures taken from the back; even if the straps are not untied, they should not obscure the deformity. 30

39 Chapter 3 The Lenke Classification: Technique for Analysis and Classification of Operative AIS A Section Editors: Lawrence G. Lenke, MD Kathy M. Blanke, RN Timothy R. Kuklo, MD Michael F. O Brien, MD Central Sacral Vertical Line (CSVL) Between Pedicles (Apical Vertebra) 31

40 Chapter 3 The Lenke Classification: Technique for Analysis and Classification of Operative AIS The Lenke Classification is a three-step system that allows a reproducibly accurate classification of adolescent idiopathic scoliosis (AIS). The system s reproducibility stems from its reliance on objective radiographic measurements obtained from standard preoperative radiographs (standing AP and lateral, right and left bending radiographs) that are used to assess regional curve flexibility. The measurements obtained from these radiographs are compared to predetermined numeric values that allow identification of structural and nonstructural curves. The result is an objective classification of AIS that has a high degree of intra- and interobserver reliability. By virtue of this system s analysis of each curve, the detailed assessment necessary for effective presurgical planning is accomplished during classification. Step #1: Identification of the Primary Curve (Types 1-6) First the regional curves are identified. These are the proximal thoracic (PT), main thoracic (MT), and thoracolumbar/lumbar (TL/L) curves. Each curve is defined by the level of its respective apex. The curve designation is then applied according to SRS nomenclature committee definitions (Figure 1). Figure 1 Curve Thoracic Thoracolumbar Lumbar Location of Apex (SRS Definition) Apex T2 through the T11 T12 disc* T12 to L1 L1 L2 disc through L4** * Regardless of the number of thoracic vertebrae, the disc below T11 is always a thoracic apex. ** In some type A curves the apex can be L5 (most horizontal segment). Technically L5 is a lumbosacral apex but that is not measured for AIS. To begin the classification, the structural or non-structural quality of each of the three curves must be determined. The first structural curve will be identified by making a determination as to which curve is the major curve. The major curve will always be the MT or TL/L, whichever is the largest curve. In very rare cases where the PT is the largest Cobb measurement, default to the MT as the major curve. The major curve will always be considered structural. The MT curve will be the major curve in types 1-4 and the TL/L curve will be the major curve in types 5 and 6. In type 4 curves (triple major), either the MT or TL/L curve can be the major curve depending on which has the largest Cobb measurement. If MT and TL/L are equal in magnitude, the MT will be considered the major curve. The minor curves (the other two curves) may be structural or nonstructural. Curves are considered structural if they are 25 on the standing AP radiograph and do not bend out to < 25 on the side-bending radiographs. Minor curves < 25 on the standing AP radiograph by definition will be nonstructural. However, minor curves may be deemed structural if their regional sagittal profile reveals a kyphosis +20. The T2-T5 sagittal alignment is evaluated in conjunction with the proximal thoracic spine. Therefore, even if the PT curve is not structural by coronal criteria (i.e., it bends out to < 25 ), but the regional kyphosis between T2-T5 is +20, the curve will be considered structural. The sagittal alignment from T10-L2 is evaluated in conjunction with the MT and the TL/L regions in a similar fashion. A kyphotic sagittal alignment from T10-L2 of +20 will cause the TL/L or main thoracic curve to be considered structural even if it does not meet structural criteria in the frontal (coronal) plane. After determining the structural or nonstructural nature of each regional curve, the Lenke type (1-6) can be assigned (Figure 2). 32

41 The Lenke Classification: Technique for Analysis and Classification of AIS Figure 2 Type Proximal Thoracic Main Thoracic Thoracolumbar/Lumbar Curve Type 1 Non-Structural Structural (Major*) Non-Structural Main Thoracic (MT) 2 Structural Structural (Major*) Non-Structural Double Thoracic (DT) 3 Non-Structural Structural (Major*) Structural Double Major (DM) 4 Structural Structural (Major*) Structural (Major*) Triple Major (TM) 5 Non-Structural Non-Structural Structural (Major*) 6 Non-Structural Structural Structural (Major*) Minor Curve Structural Criteria Side Bending Cobb 25 T2-T5 Kyphosis +20 Side Bending Cobb 25 T10-L2 Kyphosis +20 Side Bending Cobb 25 T10-L2 Kyphosis +20 Thoracolumbar/Lumbar (TL/L) Thoracolumbar/Lumbar- Main Thoracic (TL/L MT) *Major = Largest Cobb measurement always structural. Minor = All other curves may be structural or non-structural. In type 4 curves (triple major), either the MT or the TL/L curve can be major, depending on the largest Cobb measurement. If the MT and TL/L are equal in magnitude, the MT will be considered the major curve. Minor Curve Structural Criteria Coronal S.B. Sagittal PT (T2-T5) MT (T10-L2) TL/L (T10-L2) 33

42 The Lenke Classification: Technique for Analysis and Classification of AIS Bending measurements in parentheses on x-ray images TYPE 1 MT TYPE 2 DT TYPE 3 DM TYPE 4 TM TYPE 5 TL/L TYPE 6 TL/L-MT 34

43 The Lenke Classification: Technique for Analysis and Classification of AIS Step #2: Assignment of Lumbar Modifier (A,B,C) If the Center Sacral Vertical Line (CSVL) passes between the pedicles of the apical lumbar vertebra, the lumbar modifier A is assigned. If the CSVL falls between the medial edge of the concave pedicle and the lateral vertebral body on the apical lumbar vertebra, the lumbar modifier B is assigned. If the CSVL does not touch the lateral edge of the apical lumbar vertebra, the lumbar modifier C is assigned. Occasionally it will be difficult to decide between an A and B modifier, or a B and C modifier. In either situation, a B modifier should be assigned if a clear distinction cannot be made. When the apex is a disc, the lumbar modifier is determined by the position of the CSVL in relation to the vertebra immediately above and below the apical disc (Figures 3 and 5a-5c). Figure 3 A B C CSVL Between Pedicles (Apical Disc) * See stacker algorithm on page 36 CSVL Touches Apical Pedicle (Apical Body) The apical vertebral bodies are completely lateral to the CSVL (Apical Disc) 35

44 The Lenke Classification: Technique for Analysis and Classification of AIS Identifying the Lumbar Apex: To assign the lumbar modifier, the lumbar apex must be identified. The CSVL is erected from the midpoint of S1. The apex is the most horizontal and in some cases the most laterally deviated vertebra or disc from the midline (CSVL). If the lumbar curve does not cross the midline (i.e., Type A Modifier) the apex will be the most horizontal segment. If the lumbar curve partially crosses the midline (i.e., Type B Modifier) or completely crosses the midline (Type C Modifier), the apex will be the most horizontal and most laterally deviated segment from the CSVL. Identifying the Apical Vertebra/Disc for Lumbar A Curves (Figure 4) For type A modifiers in cases where everything is in the midline and two or more vertebrae are equally horizontal then the following will be selected as the apex: Figure 4 Two Stacked Vertebrae (Apex = Disc) Three Stacked Vertebrae (Apex = Middle Vertebra) Four Stacked Vertebrae (Apex = Middle Disc) 36

45 Figure 5a Lumbar Spine Modifier A The Lenke Classification: Technique for Analysis and Classification of AIS Curve Type (1 6) Type 1 (Main Thoracic) Type 2 (Double Thoracic) Type 3 (Double Major) Type 4 (Triple Major) 1A* 2A* 3A* 4A* 37

46 Figure 5b Lumbar Spine Modifier B The Lenke Classification: Technique for Analysis and Classification of AIS Curve Type (1 6) Type 1 (Main Thoracic) Type 2 (Double Thoracic) Type 3 (Double Major) Type 4 (Triple Major) 1B* 2B* 3B* 4B* 38

47 Lumbar Spine Modifier C The Lenke Classification: Technique for Analysis and Classification of AIS Figure 5c Curve Type (1 6) Type 1 (Main Thoracic) Type 2 (Double Thoracic) Type 3 (Double Major) Type 4 (Triple Major) 1C* 2C* 3C* 4C* Type 5 (TL/L) Type 6 (TL/L - MT) 5C* 6C* 39

48 Step #3: Assignment of Sagittal Thoracic Modifier (, N, +) The thoracic sagittal modifier is determined by evaluating the sagittal Cobb measurement between T5 and T12. If the T5-T12 sagittal Cobb is less than 10 degrees, the sagittal thoracic alignment is considered hypokyphotic and is assigned a minus modifier (-). If the sagittal Cobb is between 10 and 40 degrees, the sagittal alignment is considered normal (N). If the sagittal Cobb measurement between T5 and T12 is greater than 40 degrees, the sagittal alignment is considered hyperkyphotic and is assigned a plus modifier (+) (Figures 6a and 6b). Figure 6a Thoracic Sagittal Profile T5-T12 (Hypo) < + 10 N (Normal) (Hyper) > + 40 The Lenke Classification: Technique for Analysis and Classification of AIS Sagittal Thoracic Modifier : <10 N: : >40 40

49 Possible sagittal structural criteria The Lenke Classification: Technique for Analysis and Classification of AIS Figure 6b Curve Type (1 6) Type 1 (Main Thoracic) Type 2 (Double Thoracic) Type 3 (Double Major) Type 4 (Triple Major) Normal PT Kyphosis TL Kyphosis PT and TL Kyphosis *T5-12 sagittal alignment modifier:, N, or + (To determine specific curve type) : <10 N: : >40 Type 5 (TL/L) Type 6 (TL/L - MT) Normal TL Kyphosis 41

50 The Lenke Classification: Technique for Analysis and Classification of AIS Using these three simple steps and carefully adhering to the radiographic parameters for structural and nonstructural curves, 42 discrete curve classifications can be identified (Figure 7- excluding sagittal thoracic modifiers). Because the system leaves little room for artistic license in evaluating and classifying the curve, it has shown excellent intra- and interobserver reliability. Our ability to reliably classify AIS into specific subgroups (compare apples to apples) will be mandatory if we are going to evaluate the outcome of our interventions. Figure 7 Lumbar Spine Modifier Type 1 (Main Thoracic) Curve Type (1 6) Type 2 (Double Thoracic) Type 3 (Double Major) Type 4 (Triple Major) Type 5 (TL/L) Type 6 (TL/L - MT) A 1A* 2A* 3A* 4A* B 1B* 2B* 3B* 4B* C 1C* 2C* 3C* 4C* 5C* 6C* Possible sagittal structural criteria (To determine specific curve type) Normal PT Kyphosis TL Kyphosis PT and TL Kyphosis Normal TL Kyphosis 42 *T5-12 sagittal alignment modifier:, N, or + : <10 N: : >40

51 Classification Examples: The Lenke Classification: Technique for Analysis and Classification of AIS Curve Type 1: Thoracic curve major, other curves non-structural (bend out to <25 ) Lumbar Modifier A: CSVL between pedicles at apex (L5) Sagittal Modifier N: T5-T12 in the range Therefore, classification is Type 1AN 43